BS ISO 20978:2020 - Liming material. Determination of neutralizing value. Titrimetric methods

BS ISO 20978:2020

Liming material. Determination of neutralizing value. Titrimetric methods

Status : Current   Published : May 2020



This document specifies two methods for the determination of the neutralizing value (NV) of liming materials.

Method A is applicable to all liming materials except silicate liming materials.


Examples of hard liming materials are limestone and dolomite. Examples of soft liming materials are chalk, marl and burnt lime.

Method B is applicable to all liming materials.

Neither method correctly takes into account the potential neutralizing value of material containing more than 3 % P2O5. For a more accurate agronomic assessment of products containing more than 3 % P2O5, EN 14984[8] is used to determine the liming efficiency.


The methods described in ISO 6598 and ISO 7497 can be used for the determination of P 2O 5 content. Further information on P analyses is given in References [ 5] and [ 6].


Carbonate consumes H + and removes acidity in solution with subsequent dissociation to H 2O and CO 2. Forms of orthophosphate can consume H + but are not dissociated to molecular forms that remove acidity. The acidity is back titrated with alkali causing an underestimation of NV.

Standard NumberBS ISO 20978:2020
TitleLiming material. Determination of neutralizing value. Titrimetric methods
Publication Date18 May 2020
Normative References(Required to achieve compliance to this standard)ISO 14820-2, ISO 3696, ISO 3310-1, ISO 8157
Informative References(Provided for Information)EN 14984, ISO 14820-1, ISO 7497, EN 1482-3, ISO 5725 (all parts), ISO 6598
International RelationshipsISO 20978:2020
Draft Superseded By18/30334858 DC
DescriptorsLime, Tolerances (measurement), Water, Soils, Agriculture, Agricultural materials, Fertilizers, Soil improvement, Physical properties of soils, pH control
Title in FrenchAmendements minéraux basiques. Détermination de la valeur neutralisante. Méthodes par titrimétrie
ISBN978 0 580 92740 9
File Size1.693 MB

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